Small \(\lambda \)  expansion of the actual \(T\)  is given in [1]} in the explicit form in terms of the integrals of free field correlators. A comparison with \(T_{\rm guess}\)  reveals that, besides the classical \(\beta ^0\)  term, which matches the classical expression (REF ) for a constant potential \(u=h\) , only \(\beta ^2\lambda ^2\)  term coincides with, while \(\beta ^2 \lambda ^4\)  and \(\beta ^4 \lambda ^2\)  terms do not match the correct result. We thus conclude that the conjectural expression (REF ) is missing non-perturbative terms, which are not captured by the asymptotic expansion (REF ).
